Air or gas lift valves



y 30, 1967 c. R. CANALIZO 3,322,137

AIR OB GAS LIFT VALVES 2 Sheets-Sheet 1 Filed Oct. 9, 1965 -INVENTOR. CARLO S- R. CANALIZO a fi r Why-five N3 FIG. 2

y 30, 1967 c. R. CANALIZO 3,322,137

AIR OR GAS LIFT VALVES Filed Oct. 9, 1963 2 Sheets$heet 2 209 *ZIO I N VENTOR.

CARLOS R. CANALIZO United States Patent 3,322,137 AIR R GAS LIFT VALVES Carlos R. Canalizo, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas, Tex., a corporation of Delaware Filed Oct. 9, 1963, Ser. No. 314,914 13 Claims. (Cl. 137-155) This invention relates to air or gas lift valves for use in oil Wells and the like for controlling the admission of gas or air into the column of fluid in the well to lift the column and aid in flowing the fluid from the well.

In conventional gas lift systems, the well equipment includes a string of relatively small pipe called the tubing which is inserted inside a large diameter pipe called a casing. Gas is introduced into the annular space or annulus between the tubing and the casing and is injected through suitable gas lift valves located at spaced points along the tubing into the column of oil inside the tubing in order to lift the oil to the surface. The gas lift valves may be mounted exteriorly of the tubing and communicate with the interior tubing through suitable ports in the wall of the tubing or the valves may be removably mounted in special landing nipples in which suitable gas lift ports are provided connected in the tubing and wherein the valves are positioned laterally of the principal tubing bore so that the tubing bore remains open for the passage of other tools through. Alternatively, the valves may be removably positioned in the main tubing bore or they may be fixed in position in the main tubing bore. In some wells it is desirable to have such gas lift valves responsive to the pressure within the tubing bore as well as to the pressure of the gas in the annulus in order that the valve will open to permit injection of the lifting gas into the tubing only when the pressure within the tubing at the location of the gas lift valve exceeds a predetermined pressure and the pressure of the gas in the tubing also exceeds a second higher predetermined value.

An object of this invention is to provide a gas lift valve whose operation is responsive to the pressure within the tubing bore and of the lifting gas in the annulus and which closes when the pressure in the annulus drops to a value which is lower by a predetermined degree from the value thereof necessary to cause opening of the valve.

Another object is to provide a gas lift valve having a biased closure member having a section constructed of a flexible resilient material which is biased towards its closed position closing the gas admission ports of the valve and is contractible radially to open position away from said gas admission ports by the pressure of the lifting gas from exteriorly of the valve, the closure memher having a rigid section and having different predetermined areas on which act the pressure of the lifting gas, the pressure within the tubing bore, and the pressure of a biasing fluid, whereby the pressures within the tubing bore and of the lifting gas must reach different predetermined values before the closure member moves to its open position against the force exerted by the biasing fluid.

Still another object is to provide a gas lift valve wherein the area of the rigid section of the closure member on which acts the pressure of the lifting gas is increased when the closure member moves to its open position, whereby the closure member moves to its closed position only when the pressure of the lifting gas drops to a pre- "ice determined value lower than that required to permit movement of the closure member from its closed to its open position.

Another object is to provide a valve wherein the biasing force on the closure member is exerted by a charge of gas under pressure. 1

A further object is to provide a gas lift valve wherein the biasing force is exerted by a loaded spring acting on a fluid whose pressure is communicated to the closure member to bias it towards its closed position.

A still further object is to provide a gas lift valve which includes an auxiliary check valve means adapted to prevent the back flow of fluid from the tubing, the check valve being constructed of resilient flexible material.

Another object is to provide a gas lift valve whose closure elements do not depend on a fine finish or close tolerance whereby the valve may function properly even though the closure elements suffer corrosion or erosion.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed inaccordance with the invention, and reference to the accompanying drawings, wherein:

FIGURE 1 is a view partly in section and partly in elevation of a valve embodying the invention installed in an offset pocket of a mandrel of a tubing;

FIGURE 2 is a vertical partly sectional view of the valve illustrated in FIGURE 1;

FIGURE 3 is a perspective view, partly in section, of the closure member of the valve illustrated in FIG- URES 1 and 2;

FIGURE 4 is a fragmentary vertical, partly sectional view of a modified form of the valve showing it in its open position;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 4; I I

FIGURE 6 is a View partly in elevation and partly in section showing a valve embodying the invention mount ed exteriorly on the tubing of a well;

FIGURE 7 is an enlarged partly sectional vertical view of the gas lift valve illustrated in FIGURE 6; and,

FIGURE 8 is a vertical partly sectional view of the upper portions of a valve showing a spring means for biasing the closure member thereof to its closed position.

Referring now particularly to FIGURES 1 through 3 of the drawings, the gas lift valve 10 embodying the invention is shown positioned in the pocket 11 of a landing nipple 12 connectible in a string of tubing T to constitute a section thereof. The pocket maybe formed of an upper section 14 and a lower section 15 welded together and having common longitudinal bore 16 which opens upwardly. The pocket 11 is eccentrically fixed in a suitable longitudinal slot or opening 17 in the wall of the nipple in a suitable manner as by the welds 18, the pocket thus closing such slot. The pocket has an internal annular recess 19 adjacent its upper end in which are receivable any suitable lock or latch dogs 20 of the latch mandrel 21 connected to the upper end of the valve. A plurality of lateral ports 22 provide fluid communication between the exterior of the nipple and the longitudinal bore 16 of the pocket, and a discharge port 23 at the lower end of the pockets provides fluid communication 'between the lower end of the pocket and the longitudinal bore or flow passage of the string of tubing T.

The valve 10 includes a body 25 having an upper chamber section 26, an intermediate seal section 27, a

port section 28 and a bottom seal section 29. The top body section has a reduced threaded end portion 31 by a means of which the locking mandrel 21 may be secured to the upper end of the body. The locking mandrel may be of any well known type and whose dogs 20 are adapted to move'outwardly into the locking recess 19 to hold the locking mandrel and the valve releasably in the pocket. An external annular upper flange 34 adjacent the upper end of the locking mandrel is engagea-ble with the upper end of the pocket 11 to limit downward movement of the mandrel in the pocket and a fishing neck or gripping head 35 at the top end of the locking mandrel is engageable by a suitable running or retrieving tool, not shown,

for'inserting the valve into or removing it from the pocket.

The intermediate seal section 27 has an upper end portion threaded into the lower end of the top portion 26, and a suitable packing assembly 37 which may be of the chevron type is disposed thereon. The seal assembly is held against longitudinal displacement on the body by the downwardly facing annular inverted V-shaped surface 38 at the bottom end of the top body section, in which the uppermost chevron seal element is received, and the upwardly facing shoulders 41 and 42 of the seal body section 27 and the top end surface of the port body section 28. The annular upwardly facing shoulder 41 is provided by the external flange 44 of the seal body sectionon which is threaded the upper end portion of the port body section. The seal retainer ring 46 is interposed between the lowermost chevron seal element and the shoulders 41 and 42.

The port bodysection 28 has an internal annular flange 48 which provides an annular u wardly facing seal surface 49 and a longitudinal internal annular seal surface 50. Radially spaced elongate slots or ports 52 of the body section open through the annular seal surface 49 intothe port body section above the internal flange 48 and also radially inwardly through the enlarged diameter longitudinal upper seal surface 50 of the port body section above the flange 48. V

A substantially tubular closure member SS is secured to the intermediate seal body section 27 by a tubular closure retainer 57 having an external annular flange 58 at its lower end which provides the upwardly facing annular shoulder 59, which shoulder is held in spacedrelation below the bottom surface 60 of the intermediate seal body section 27 'by an upwardly facing annular shoulder 62 engageable with said bottom surface. The threaded upper end portion 63 of the reduced external diameter of the closure retainer extend-s upwardly through the intermediate seal body section 27 and is secured thereto by a includes a resilient tubular section 67 having an internal annular flange 68 at its upperend which extends into a the annular recess 68a whose lower and upper sides are defined by'the shoulder 59 of the closure retainer'and the bottom surface 60 of the intermediate seal body section 27. The inherent longitudinal length of the internal flange 68 of the closure 55 is somewhat greater in the height and width of the recess 68a so that the upper portions of the resilient tubular sections are compressed into sealing engagement with the retainer closure, the intermediate seal body section and the internal surfaces of the port body section 28. If desired, the external surface of the closure retainer between the shoulders 62 and 59 may be provided with serrations into which the resilient substance of the tubular section may flow as the flange 68 is compressed. Similarly, the intern-a1 surface of the port section 29, as at 70, may be provided with similar serrations. Such serrations provide a good seal and bond between the tubular section and the surfaces of the valve body and the closure retainer. An O-ring or other suitable seal 73 disposed in an external annular recess of the intermediate seal body section seals between the intermediate seal section and the top section thereof. The tubular section 67 of the closure member has an internal annular.

bottom flange 75 provided with an internal annular recess 76 in which is received and bonded the external annular flange 77 of a rigid disk insert 78 which closes the lower end of the tubular section. The annular downwardly and inwardly beveled or inclined seat surface 79 of the disk insert is engageable with'the annular beveled seat 80 of seal surface 50 at the ports 52 when the pressure exteriorly of the body exceeds the pressure in the pressure or charge chamber of the body. The charge chamber is provided by the longitudinal bores of the top body sectionand the closure retainer and is closed at its lower end by the closure member 55. j A compressible gas is introducible into the charge chamber through a filler port 86 of the top body section which is closable by a suitable plug 87 threaded in the outer enlarged portion of the filler port. 7

A check valve assembly 90 is mounted in the body 25 below the closure member and'includes a cylinder 91' whose bottom end is closed by its end portion 92 and whose open upper end is threaded in the lower end por tion of the internal flange 48 of the port body section 29 as at 93. The check valve cylinder has a plurality of lateral apertures 95 which are closable by the resilient tubular check valve 97 disposed about the check valve cylinder. The internal diameter of the check valve is slightly greater than the external diameter of the check valve cylinder so that a very small cylindrical passage is normally provided therebetween through which fluids may flow at very slow velocity into the apertures 95. Such cylindrical passage however is closable quickly whenever any appreciable upwardly flow tends to take place due to an increased pressure differential between the in-.

terior and exterior of the cylinder, since the resilient check valve is then moved by such pressure differential into sealing engagement with the cylinder closing the apertures or ports thereof. The check valve has an external annular.

flange 99 at its upper end disposed between the lower annular surface or shoulder 100 of the flange 48 and the 7 top annular end surface or shoulder 1020f the bottom 7 body section 29 which is threaded in the lower end of the port body section 28. The bottom body section has an internal annular flange 104 which engages the outer surface of the resilient tubular check valve 97 below its external flange so that the upper portions and the flange 99 of the check valve are compressed and sealingly engage the check valve cylinder, the port body section and, the bottom section of the body, and so that the lower portions of the check valve are free to expand resiliently outwardly to permit fluid from the passage of the body.

to the bore or passage 112 of the bottom body section through theapertures 93 of the check valve cylinder, and thence downwardly and outwardly through the ports 113 of the bottom body section.

A seal assembly 114 is disposed on the bottom body section and is held against upward' movement therefrom by the engagement of the downwardly facing annular end surface or shoulder 115 of the port body section with the retainer ring 116 of the seal assembly. Downward movement of the seal assembly on the bottom body section is limited by the engagement of the bottom chevron seal element thereof with the external upwardlyfacing annular surface 118 of the bottom body section which defines a substantially V-shaped slot.

In use, the top chamber 85 of the valve is ch arged with a compressible fluid through the inlet port 86 thereof to a predetermined pressure and the inlet port '86 is then closed by the plug 87.

The pressure of the fluid in the charge chamber expands the cylindrical portion of the resilient tubular section 67 of the closure member 55 outwardly into sealing engagement with the internal seal surface of the valve body and simultaneously moves and biases the lower end of the closure member downwardly, first causing the lower portion of the internal flange 75 of the tubular section to be compressed into sealing engagement with the annular seal surface 49 of the valve body and then causing the annular seat 79 of the disk section 78 thereof to engage annular seat 80 of the body to thus limit downward movement of the disk section and the compression of the internal flange 75. The engagement of the internal flange with the seal surface 49 closes the bore or passage 110 between the ports 52 and 113. The engagement of the seats 79 and 80 may also provide a seal for this purpose.

The locking mandrel is then secured to the upper end of the valve body and the assembly of the gas lift valve and the locking mandrel is then lowered into the string of tubing in a well known manner by means of a flexible lowering mechanism and into the landing nipple and then moved laterally in the landing nipple in a manner well known in the art to position the valve in alignment with the upper end of the pocket 11. The valve is then lowered in the pocket until its downward movement is stopped by the engagement of the flange 34 of the locking mandrel with the upper end of the pocket. The latch or dog means 20 of the locking mandrel is cammed resiliently inwardly against a biasing means in the locking mandrel as the valve is lowered into the pocket and then are moved outwardly into the locking or latch recess 19 by the biasing means as the latch or dog means move into alignment therewith. The latch means then releasably holds the valve in the pocket in the position illustrated in FIGURE 1. The upper and lower seal assemblies 37 and 114 sealingly engage the internal surface of the pocket 11 above and below, respectively, the lateral ports 22 in the wall of the pocket and direct lifting gas flowing through the ports into the pocket to the slots 52 of the valve body.

Oil, or other earth formation liquid, then enters into the lower open end of the tubing (not shown) and rises to a level therein determined by the formation pressure. The formation liquid in the tubing T cannot flow outwardly through the gas lift valve since the closure member 55 is now in its closed position and in addition, since the check valve 97, while permitting a gradual or very slow flow of fluid and thus communication of pressure from the tubing into the tubular passage 11%, moves to its closed position when the pressure differential between the bores 110 and 112 increases to any appreciable value.

If the formation pressure is such that the formation fluids will not flow upwardly to the surface through the tubing, gas or air, herein referred to as gas generally, is introduced into the annular space or annulus A between the string of tubing T and the string of casing C, in order for the gas to be injected through the gas lift valve to the column of fluid in the tubing. While the pressure of the gas in the annulus is below the pressure of the charge of gas in the chamber 85 of the valve, the closure member 55 remains in its normal expanded closed position in which it closes the slots 52 of the valve body, and also holds the disk section 58 biased downwardly with its seat 79 in engagement with the seat 86 and also holding the internal flange 75 in sealing engagement with the seat 49 of the valve body. The disk section 78 of the closure member 55 has a relatively large downwardly facing area on which acts the pressure of the fluid in the tubing, such area being defined by the annular line of sealing engagement of the seats 7 9 and 80 or, if such seats do not provide a seal, the annular line of sealing engagement of the internal flange 75 of the resilient tubular section 67 with the seat surface 49 of the valve body. The pressure in the annulus A also acts on the downwardly facing area of the closure member extending outwardly of such line of sealing engagement of the internal flange of the resilient closure section with the seat surface 49 of the valve body. The tubing pressure and the annulus pressure thus both bias or tend to move the closure member upwardly and out of sealing engagement with the seat 49. The ratio between these two areas exposed to the tubing and annulus pressures, respectively, may be varied by varying the diameters of the seat surfaces 79 and 49 of the valve body. It will be apparent that if the central area of the downwardly facing surfaces of the closure member acted upon by the tubing pressure is enlarged in comparison to the area acted upon by the pressure from the annulus, the valve will be more sensitive to the tubing pressure than to the casing pressure, and, conversely, if the area acted upon by the tubing pressure is small in comparison to the downwardly facing area acted upon by the pressure from the annulus, the valve will be more sensitive to the annulus pressure.

For example, the valve may be of such dimensions that the downwardly facing area of the closure member upon which the tubing pressure exerts an upwardly acting force is 0.2 square inch, that the downwardly facing area upon which the casing pressure exerts an upwardly acting force is 0.4 square inch, and that the upwardly facing area upon which the pressure of the compressed gas in the chamber exerts a downwardly acting force is 0.6 square inch. If the chamber pressure is 500 lbs. per square inch, the closure member is biased towards its closed position by a total force of 300 lbs. If the gas in the annulus A is maintained at a pressure of 525 pounds at the valve, it exerts an upwardly acting force of 210 pounds tending to move the closure member upwardly out of engagement with the seat 49. In order for the valve to open the pressure in the tubing must exert an upward force of pounds on the closure member, which requires that a pres sure of 450 pounds per square inch be present in the tubing at the location of the valve. Under normal operating conditions, with the annulus pressure maintained at 525 pounds per square inch, production fluids rise in the tubing to form a column above the inlet ports 52 of the valve body until the hydrostatic pressure at this location increases to or slightly above 450 pounds per square inch, at which time the closure member is moved upwardly and the gas from the annulus flows through the gas lift valve into the tubing and lifts the well fluids to the surface. Once the valve closure member moves to its open position, the whole downwardly facing area of 0.6 square inch of the closure member is exposed to the higher annulus pressure of 525 pounds per square inch. The gas lift valve will therefore remain open even though the annulus pressure drops below 525 pounds per square inch as the well fluids are lifted to the surface and discharged and as the annulus pressure diminishes due to the flow of gas into the tubing therefrom. The force of the charge of compressed gas, which is 500 pounds per square inch, will therefore move the closure member to its lower seated position when the annulus pressure decreases to slightly less than 500 pounds per square inch. As a result, the gas lift valve will open only when the annulus pressure is 525 pounds per square inch and a column of well fluids in the tubing above the gas lift valve exerts a hydrostatic pressure of 450 pounds per square inch on the closure member, and will close only when the annulus pressure decreases to 500 pounds per square inch, thus providing a spread of 25 pounds per square inch between the valves of the annulus pressure at which the valve opens and closes.

If desired, any suitable intermitter valve can be used to cause intermittent or periodic operation of the gas lift valve by injecting gas into the annulus at the surface at periodic intervals to increase the annulus pressure therein at the ports 52 to 525 pounds per square inch at such times when the hydrostatic pressure in tubing at the valve reaches 450 pounds per square inch. The intermitter is, of course, properly timed to control the opening of the gas lift valve by building up the annulus pressure to the required value at proper times. The gas lift valve can be caused to open when the column of well fluids in the tubing above the valve is of lesser height by increasing the annulus pressure to a higher value. It will thus be opening of the valve. 7

It will further be seen that the gas lift valve is provided with a new and improved closure member 55 and closure member retainer 57, and that the closure member has resilient section and a rigid section exposed to the pressure of the annulus, the tubing bore and a charge of compressed gas which biases the closure member to close the valve.

It will further be seen that the closure member has a rigid section or disk 78 which is acted upon by the pressure of the charge of compressed gas in the annulus and tubing pressures, it being apparent that if the closure member were made entirely of a resilient substance, the operation of the gas lift valve would be responsive to the casing pressure only and the valve would open when the casing pressure increased above the pressure of the charge of compressed gas and close when the annulus pressure decreased below the pressure of the charge of compressed gas.

It will further be seen that the closure retainer member 57 limits radial contraction of the cylindrical portions of the resilient tubular section of the closure member and the internal surface 50 of the body limits radial expansion of the tubular section, thus protecting the closure member against excessive deformation and damage.

It will further be seen that the annular space between the external surface 81 of the retainer and the internal surface 50 of the body is greater in width than the radial thickness of the resilient tubular section of the closure member so that the lower portions of the closure. member have room to contract readily inwardly and the extreme lower end portions then have room to deform radially outwardly as the lower closed end portions of the closure member is moved upwardly away from the seat 49.

It will further be seen that the bottom end surface 82 of the retainer limits such upward movement of the bottom or closed end portion of the closure member.

It will further be seen that the gas lift valve is of simple, easily assembled construction and that it includes a check valve assembly 90 which prevents reverse flow of fluids from the tubing to the exterior thereof.

It will further be seen that the gas lift valve includes a tubular bodyhaving a longitudinal bore divided into a chamber 85 and a passage 110 by the closure member, that the flow passage opens to the exterior of the body at longitudinally spaced locations therealong, and that the body has external seal means disposed above the upper end of the passage and between the upper and lower ends of the passage.

It will further be seen that the body has a seat surface, such as 49, which is engageable by a closure meme ber 55 disposed in the body which closes the lower end of a charge chamber 85 of the body and which is biased to engagement with the seat to close the flow passage of the valve by the pressure exerted thereon by a fluid in the charge chamber.

Referring now to FIGURE 4 of the drawings, the gas lift valve 150 is similar. in structure and mode of operation to the gas lift valve 10 and, accordingly, ele- 8 ments of the gas lift valve 150 have been provided with the same reference numerals, to which the suflix a has been added, as corresponding elements of the gas lift valve 10.

The gas lift valve 150 differs in structure from the' gas lift valve 10 in that the port body section 28a thereof includes an upper tubular portion 151 threaded 'on the lower end of the seal body section 2712 and provided with an internal annular flange 152 at its lower end.

The flange has a plurality of circumferentially spaced vertical bores or ports 153 extending upwardly from its bottom surface and a plurality of concentric grooves 154, extending downwardly from its topsurface, which open into the upper ends of the vertical bores 153 so that fluids may flow upwardly through the ports 153 and the annular grooves 154 from the exterior of the bodyto the bore or interior passage 155 thereof below the closure member 55a. The intermediate tubular portion 156 of the port body section 28a extends upwardly into the internal flange 152 and is rigidly secured thereto, as by welding or soldering, and extends downwardly into and is connected in a similar manner to the tubular bottom portion 157 of the port body section 2811. The check valve cylinder 91a is threaded into the internal flange 158 of the bottom portion 157. The intermediate tubular portion provides an annular seat 160 which is engage able by the internal annular flange 75a of the closure member 5511. The bottom body section 29a is of course,

threaded into the lower end of the bottom portion 157 of port body section 28a.

It will. be apparent that the gas lift valve 150 functions in exactly the same manner as the valve 10 but may be preferable to the valve 10 due to the ease and simplicity of manufacture of the port body section 28a as compared to the port body section 28 of thevalve 10.

Referring now particularly to FIGURES 6 and 7 of shown, of which it constitutes a section. The nipple 201 has an injection lug 202 provided with an injection passage 203 which communicates with the interior or bore of the nipple through an injection port 204. thereof. The upwardly opening upper end portion of the injection pas sage is threaded and receives the reduced lower end portion 205 of the bottom body section 2% of the valve body 25b. A protective guide lug 207 may be welded to the exterior of the nipple above the upper end of the valve to prevent damage to the valve as the tubing is lowered into or pulled from casing C. The bottom 7 body section engages the external top flange 99b of the check valve sleeve 97!) to sealingly hold it in engagement between the check valve cylinder 91b and the port 7 having a charging valve 210 threaded in an opening in:

the upper end thereof. A plug 211 threaded into the sub above the charging valve. The charging valve permits flow therethrough into the chamber 851) of the valve but prevents reverse flow from the chamber. The charging valve may be similar to the well known pneumatic valves used for introduction of air into pneumatic tires. A protective cap 212 is threaded onto the upper end 213 of the sub.

to protect the plug from damage. 7

It will be apparent that the valve 200 is mounted on the exterior of the nipple and therefore is not provided with the external seal assemblies, such as the seal assemblies 37 and 114 of the valve 10. The valve 200 functions in the same manner as the valve 10 permitting flow of lifting gas from the annulus A between the tubing and the casing C into the tubing through the ports 52b of the valve body, check valve cylinder 91b, its port 95b, the bore 11217 of the lower body section, the injection flow passage 203 of the injection lug 202 and the injection port 204 of the nipple when the pressure in the annulus attains a predetermined value and the column of well fluids in the tubing above the valve attains a predetermined height; and closes when the pressure in the annulus falls to a value below the pressure of the charge of gas in the charge chamber 85b.

The valves 10, 150 and 200 have been described and illustrated as having a charge of compressed air in their charge chambers for biasing the closure member towards its expanded or closed position. Such gas charged valves however have the disadvantage in some conditions of well operations in that the pressure of the gas charge varies in accordance with the changes in temperatures. In installations where such temperature changes may affect the operation of the gas lift valve by varying the pressures of the tubing and annulus pressures at which the valve opens, the force for biasing the closure member to its closed position may be provided by a spring 300 as in the gaslift valve 301. The valve 301 is substantially identical in structure and mode of operation as the gas lift valve 10 and accordingly elements of the gas lift valve 301 have been provided with the same reference characters, to which the suflix c has been added, as the corresponding elements of the gas lift valve 10. The top section 26c of the body 25c of the valve is tubular in form, its lower end being threaded on the body section 270 and its upper end being closed by a connector sub 303. The lower end of the connector sub is threaded in the upper end of the top body section 26c and its top threaded reduced portion 304 may be secured to a looking mandrel, such as the locking mandrel 21. An O-ring or other suitable seal means 305 is disposed in an external annular recess of the plug 393 to seal between the plug and the top section.

A body of incompressible liquid 306 fills the lower end of the chamber 85c and thus fills the interior of the closure member secured to the lower end of the retainer which is identical to the closure member 55 of the gas lift valve 10. The spring 300 holds the liquid under pressure by means of a resilient cup or piston 307, slidable in the top body section 260, on which a downward force is exerted by a follower or disk 308 against which the lower end of the biasing spring bears. The upper end of the biasing spring bears against a compression adjusting spring disk or nut 309 threaded in the upper end portion of the top body section 260. The top end of the nut 309 is provided with a transverse slot 310 in which the blade of a screwdriver or like tool may be inserted to facilitate its rotation and therefore adjustment of the longitudinal position of the nut in the top body section and the compressive force with which the spring holds the liquid 396 under pressure.

It will now be apparent that the biasing or fluid means under pressure in the chamber of the valve body of any one of the several different gas lift valves embodying the invention may either be a charge of compressed gas or a liquid 306 which is held under pressure by a biasing spring 300.

It will further be seen that each form of the gas lift valve embodying the invention includes a body having a chamber, such as the chamber 85, a passage which opens at longitudinally spaced positions on the body to the exterior thereof, and that the chamber is closed by a resilient closure member which is expansible by a fluid means under pressure in the chamber to close the passage.

It will further be seen that the closure member is subit) stantially tubular in form, having a rigid section closing the bottom end thereof, and that the body has a seat engageable by the bottom end of the closure member, the closure member, when in its expanded position, having downwardly facing surfaces thereof exposed to the pressures at longitudinally spaced locations exteriorly of the body and having an upwardly facing surface exposed to the force of a biasing fluid means, the charge of gas in the chambers of the gas lift valves 10, and 200, or the liquid 306 in the chamber 850 of the valve 301.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the the spirit of the invention.

I claim:

1. A valve including: a tubular body having a longitudinal bore; a closure member secured in said longitudinal bore and dividing said bore into a closed pressure chamber and a flow passage, said body having inlet port means communicating with said flow passage adjacent said closure member and outlet port means communicating with said flow passage at a point spaced longitudinally from said closure member; said body having an internal annular seat in said flow passage between said ports; said closure member being engageable with said seat to close 01f flow through said flow passage between said ports; said closure member comprising a rubber-hke resilient flexible tubular section secured at one end to said body and having its other end free for movement in said body, and having a rigid inflexible center section closing said free end of said tubular section, said rigid section and the adjacent annular resilient portion of said closure member engaging said seat means and having a surface of predetermined area exposed to fluid pressure in said flow passage, whereby said fluid pressures in said flow passage act on said closure member to move said closure member out of sealing engagement with said seat to permit fluid flow in said flow passage between said inlet and outlet ports; and fluid pressure charge means confined in said closed pressure chamber biasing said free end portion of said closure member into sealing engagement with said seat in opposition to said fluid pressures in said flow passage to close off said flow passage to fluid flow between said ports.

2. The valve of claim 1, and retainer means in said chamber engageable with said closure means for limiting movement of said closure means away from said seat.

3. The valve of claim 1, wherein said rigid section of said closure member has a surface of predetermined area exposed to the pressure of said fluid pressure charge means which biases said closure member with a predetermined force toward said seat, said rigid section having a pair of surfaces of predetermined areas exposed to fluid pressures from the exterior of the body through said ports whereby said exterior fluid pressures tend to move said closure member against the force of said fluid pressure charge means out of sealing engagement with said seat to permit fluid flow in said flow passage between said ports.

4. The valve of claim 3, wherein both of said pair of surfaces are exposed to the fluid pressure from one of said ports when said closure member is out of sealing engagement with said seat.

5. A valve including: a tubular body having a longitudinal bore; a closure member secured in said longitudinal bore and dividing said bore into a pressure chamber and a flow passage, said body having inlet port means communicating with said flow passage adjacent said clo sure and outlet port means communicating with said flow passage at a point spaced longitudinally from said closure member; said body having an internal annular seat in said flow passage between said ports; said closure member being engageable with said seat to close ofl flow through said flow passage between said ports; said closure V l 1 member comprising a rubberlike flexible resilient tubular section secured at one end to said body and having its other end free for movement in said body, and having a rigid inflexible center section closing said free end of said tubular section, said rigid section and the adjacent annular resilient portion of said closure member engaging said seat means and having a surface of predetermined area exposed to fluid pressures in said flow passage, whereby said fluid pressures in said flow passage act on said closure member to move said closure member out of seating engagement with said seat to permit fluid flow in said flow passage between said inlet and outlet ports; and fluid pressure means in said pressure chamber biasing said free end portion of said closure member into sealing engagement with said seat to close off said flow passage to fluid flow between said ports, said rigid section of said closure member having a surface of predetermined area exposed to the pressure of said fluid means which biases said closure member with a predetermined force toward said seat, said rigid section having a pair of surfaces of predetermined areas exposed to fluid pressures from the exterior of the body through said ports whereby said exterior fluid pressures tend to move said closure member out of sealing engagement with said seat to -permit fluid flow in said flow passage between said ports, both of said pair of surfaces being exposed to the fluid pressure from one of said ports when said closure member is out of sealing engagement with said seat, and a tubular retainer disposed in said chamber and rigidly secured to said body and coacting with said body to secure said one end of said flexible resilient tubular section of said closure member to said body, said retainer having an end portion spaced from an internal surface of said body, said end portion and said internal surface defining an annular space, said tubular section having an end portion disposed in said annular space, said retainer and said internal surface being engageable by said tubular 7 section to limit radial contraction and expansion of said tubularrsection, said retainer being engageable by said rigid section to limit movement of said rigid section away from said seat.

6. The valve of claim 1, wherein said fluid pressure charge means in said pressure chamber comprises a charge of compressible gas.

7. The valve of claim 1, wherein said fluid pressure charge means comprises a body of liquid in said pressure chamber, piston means slidable in said chamber and confining said body of liquid in said pressure chamber between said piston means and said closure means, and spring means confined in said chamber and engaging said piston means to bias said piston means toward said clo- ,sure member for holding said liquid under pressure. 7

rof lateral openings formed therein providing flow pas- :sages between the interior and exterior of said tubular body and opening to said flow passage between said seat a :and saidone of said ports, and an elongate cylindrical tubular rubber-like resilient sleevee disposed about said check valve body and normally spaced therefrom to permit flow through said openings in either direction, whereby said closure member of said valve is movable in re- :sponse to said fluid pressure from said one of said ports 'in said flow passage of said valve, said resilient sleeve being movable by a predetermined flow of fluids from said one of said ports toward said seat to prevent flow in such direction through said lateral openings to the valve seat and closure member in said flow passage.

9. In a valve having a bore therein and having inlet and outlet ports formed therein communicating with said bore and providing therewith flow passage through said body, said valve also having 'a resilient closure member in said bore adjacent one of said ports defining a closed chamber in said bore, and a valve seat in said flow passage engageable by said closure member for controlling flow through said passage; biasing means for biasing said closure member toward expanded position engaging said seat for closing said flow passage to flow therethrough comprising a body of liquid in one end of said chamber and in contact within said closure member; a movable piston means in said chamber confining said body of liquid between said movable piston means and said closure member; and spring means biasing said movable means toward said closure member for holding said liquid under pressure.

10. A valve comprising: a tubular body having a longi- ,tudinal bore closed at its upper end; a closure member off flow through the flow passage of said body, said closure member having a resilient tubular section who upper end is secured to said body and opens unwardly into said chamber and whose bottom end is formed with an internal annular resilient flange section and a central inflexible rigid section whereby the bottom end of said closure member is closed by said rigid section; means confined in said closed pressure chamber biasing said bottom end of the closure member downwardly against the fluid pressures in said flow passage towardfsealing engagement with said seat, said body having'longitudinally spaced upper and lower ports communicating the exterior of said body with said flow passage above and below said seat.

11. The valve of claim 10, wherein said closuremember has a first downwardly facing area acted on by the pressure of fluid in said flow passage below said seat and a second downwardly facing area acted on by the pressure in said flow passage above said seat, said first and second surfaces both being acted on by the pressure in said flow passage above said seat when said closure member said rigid section extends radially outwardly of said seat 7 above the lower surface of saidinternal flange.

13. A valve comprising: a tubular body having a longitudinal bore closed at its upper end; a closure member secured in said longitudinal bore and dividing said bore into an upper chamber and a lower flow passage, said body having an annular upwardly facing seat surface about said flow passage and below said closure member and engageable by said closure member to close off flow through the flow passage of said body, said closure member having a resilient tubular section whose upper end is secured to said body and opens upwardly into said c'ham ber and whose bottom end is formed with an internal annularresilient flange section and a central inflexible rigid section whereby the bottom end of said closure member is closed by said rigid section; means in said chamber biasing said bottom end of the closure member downwardly toward sealing engagement with said seat, said body having longitudinally spaced upper and lower ports communicating'the exterior of said body withsaid flow passage above and below said seat, said resilient internal annular flange at .the bottom end of said closure member having its lower surface engageable with said seat and said rigid section extending radially outwardly of said seat above the lower surface of said internal flange, and a tubular retainer in said chamber secured to said body and coacting with said body to secure the upper end of said closure member between said retainer and said body,

said retainer having a lower end portion .telescoped in References Cited UNITED STATES PATENTS Langdon 251-38 X Lundberg 251-45 X Boynton 137155 Walton 103-232 Paille 251-45 X Woods 25157 Canalizo 137155 Hunter et a1. 25146 X Bicking 137155 M. CARY NELSON, Primary Examiner.

LAVERNE D. GEIGER, A. ROSENTHAL,

Assistant Examiners. 

1. A VALVE INCLUDING: A TUBULAR BODY HAVING A LONGITUDINAL BORE; A CLOSURE MEMBER SECURED IN SAID LONGITUDINAL BORE AND DIVIDING SAID BORE INTO A CLOSED PRESSURE CHAMBER AND A FLOW PASSAGE, SAID BODY HAVING INLET PORT MEANS COMMUNICATING WITH SAID FLOW PASSAGE ADJACENT SAID CLOSURE MEMBER AND OUTLET PORT MEANS COMMUNICATING WITH SAID FLOW PASSAGE AT A POINT SPACED LONGITUDINALLY FROM SAID CLOSURE MEMBER; SAID BODY HAVING AN INTERNAL ANNULAR SEAT IN SAID FLOW PASSAGE BETWEEN SAID PORTS; SAID CLOSURE MEMBER BEING ENGAGEABLE WITH SAID SEAT TO CLOSE OFF FLOW THROUGH SAID FLOW PASSAGE BETWEEN SAID PORTS; SAID CLOSURE MEMBER COMPRISING A RUBBER-LIKE RESILIENT FLEXIBLE TUBULAR SECTION SECURED AT ONE END TO SAID BODY AND HAVING ITS OTHER END FREE FOR MOVEMENT IN SAID BODY, AND HAVING A RIGID INFLEXIBLE CENTER SECTION CLOSING SAID FREE END OF SAID TUBULAR SECTION, SAID RIGID SECTION AND THE ADJACENT ANNULAR RESILIENT PORTION OF SAID CLOSURE MEMBER ENGAGING SAID SEAT MEANS AND HAVING A SURFACE OF PREDETERMINED AREA EXPOSED TO FLUID PRESSURE IN SAID FLOW PASSAGE, WHEREBY SAID FLUID PRESSURES IN SAID FLOW PASSAGE ACT ON SAID CLOSURE MEMBER TO MOVE SAID CLOSURE MEMBER OUT OF SEALING ENGAGEMENT WITH SAID SEAT TO PERMIT FLUID FLOW IN SAID FLOW PASSAGE BETWEEN SAID INLET AND OUTLET PORTS; AND FLUID PRESSURE CHARGE MEANS CONFINED IN SAID CLOSED PRESSURE CHAMBER BIASING SAID FREE END PORTION OF SAID CLOSURE MEMBER INTO SEALING ENGAGEMENT WITH SAID SEAT IN OPPOSITION TO SAID FLUID PRESSURES IN SAID FLOW PASSAGE TO CLOSE OFF SAID FLOW PASSAGE TO FLUID FLOW BETWEEN SAID PORTS. 